1. Field of the Invention
The present invention relates to a method and apparatus for bonding external leads of a solid-state device to lead frames and substrates.
2. Prior Art
Conventional methods and apparatus for bonding external leads of a solid-state device to a lead frame and substrate (collectively called "lead frames") is described, for example, in Japanese Patent Application Publication Nos. 63-20846 and 63-20847.
In this prior art, a solid-state device which has been punched out of a film carrier is held by a vacuum suction-arm. One point of the external lead of the solid-state device is first detected by a camera so that positional discrepancies in the X-Y direction of the solid-state device can be detected. The data thus obtained is then processed by a recognition unit, and the relative positional discrepancy between the position of the solid-state device and the position of the lead frame is calculated. This calculated data is fed back to a movement control section of an X-Y table which moves the solid-state device, so that the solid-state device is set at a predetermined position on the lead frame. Bonding is then performed.
In the above prior art, only discrepancies in the X-Y direction of the solid-state device can be corrected, and no consideration is given to any discrepancies in the horizontal rotational direction O. As a result, a high degree of precision is not obtained.